In an article entitled Articulated Connector, Railway Locomotives & Cars, March 1969, an articulated connector for use between adjacent container cars supported by a common truck is disclosed. The article does not indicate that side bearings between the respective car ends are utilized.
However, previous side bearing constructions for articulated railway cars utilizing similar articulated connectors have included extensions or arms extending outwardly from opposite ends of the adjacent cars on either side of the articulated connector between the cars, supported by the truck. In one construction the extensions overlap and are vertically spaced. Roller bearings separate the vertically spaced extensions, which allow one car body to pivot relative to the adjacent car body as curves are transversed (CO/BO Whooper hopper car No. 300011). Vertical loads applied to the car body must be transmitted through the adjacent car body before being transmitted to the truck bolster. Since the side bearing assembly is not spring loaded the wear surfaces become concave during continued use resulting in an increase in side bearing clearance.
In another construction, the extensions are laterally spaced and rest upon roller bearings longitudinally spaced on the transverse truck bolster center line (Santa Fe "Six Pack" Car No. ASTF 298999). This arrangement results in an unsymmetrical loading of the truck bolster with respect to the truck bolster transverse centerline between the side frames when the respective side bearing loads from each adjacent car body are not equal or in phase. This unsymmetrical loading condition results in a moment reaction at the center plate connection which is believed to adversely affect the wear characteristics of the car body center plate and truck bolster center plate bowl. Moreover, the truck bolster must be modified by the use of a saddle type structure to support the individual roller bearings on the vertical faces of the truck rather than on the upper surface of the truck as conventionally applied.
One commercially available side bearing normally used on non-articulated cars is mounted on the truck bolster, and includes rubber pads which support a metal pad upon which rest extensions or projections of the car body. However, it is not believed that such side bearings have been used previously on trucks supporting articulated cars.